The present invention relates to a dicing machine for cutting a semiconductor wafer and, more particularly, to a dicing machine having means for setting a cutting position of a semiconductor wafer.
Where a semiconductor wafer is cut by a dicing machine, it is necessary to maintain constant the infeed depth into semiconductor wafers formed by a cutting blade in order to maintain the machining quality constant.
Accordingly, in the prior art techniques, a given reference position has been established, as described, for example, in Utility Model Laid-Open No. 118609/1991. A position spaced a given distance from this reference position is taken as an infeed position. In the reference position, the cutting edge of the blade is detected when not in contact. The blade is moved a certain distance from this reference position. In this way, the edge of the blade is placed in the infeed position.
In the above-cited bulletin, the edge of the blade is placed in a position Hi where a groove is formed by a machining operation. This position Hi is detected. Also, the position H2 of the edge of the blade is detected by an optical detection means installed in the reference position. The edge of the blade is placed in a position that is given by adding (H1-H2) to H2.
In the prior art techniques, the position H1 at which the groove is formed is at a given height above the machining table and so it has been necessary to bring the blade into contact with the machining table at least once to find the H1-H2).
When either the machining table or the optical detection means is subjected to maintenance, the value of the (H1-H2) varies. Therefore, in order to find this, it is necessary to bring the blade into contact with the machining table.
In this way, in the prior art method, the blade is brought into contact with the machining table and so the blade is damaged. As a result, the life of the blade is shortened. Also, the semiconductor wafer is chipped, thus deteriorating its quality.